The spleen collected from 45 apparently healthy White Pekin ducks during the postnatal life of 155 days were processed for histological observations. The spleen was enclosed in a thin connective tissue capsule which increased in thickness as age advanced. In day old birds the parenchyma of spleen consisted of densely packed lymphoid tissue embedded in a network of reticular fibers. Only after 15 days of age the parenchyma could be clearly differentiated into red and white pulp. The histological structure of spleen attained adult pattern by 95–110 days of age. The white pulp was seen as diffuse areas of lymphoid tissue enveloping central arteries. Germinal centers were present in all the birds aged above 95 days. The red pulp was composed of loose spongy tissue arranged into anastomosing splenic cords separated by venous sinuses. Within the cell cords lymphocytes, macrophages and blood cells were present.
White Pekin ducks, spleen, postnatal development
